Chem Lab Project 2
Investigating the Determining Characteristics of Cations and Anions
Chem 111 Sec 560
Introduction: The purpose of this lab was to study the specific characteristics of cations and anions, and ultimately to be able to identify an unknown substance based on our studies and tests using the logic trees developed through the experiment. A logic tree is a graphical display of the findings from this lab which, through a series of yes/no questions, elimination tests, will help us to identify and unknown sample. This lab will result in 2 logic trees, one for identifying cations and the other, anions.
The lab was broken into three parts: Part 1 dealt with identifying a cation, Part 2 an anion, and finally
Part 3 an unknown salt mixture of anions and cations was identified using the same tests in Part 1 and
2.
Materials and Methods: Part 1: Cation Analysis: The experiment was performed on 4 cations: K+,
Zn2+, Cu2+, and Co2. To begin the elimination and confirmation tests, 4 centrifuge tubes were prepared by adding 10 drops of each known cation in metal solution; the tubes were labeled accordingly. The first test performed was the Metal Hydroxide Test, wherein drops of 6 M NaOH were added dropwise to each tube until a precipitate was formed, or a total of 20 drops were administered. This process was repeated for each tube, with drops administered until a precipitate was visible. Drops were administered as follows:K+: 20 drops, Zn2+: 3 drops, Cu2+: 2 drops, Co2+: 2 drops 6 M NaOH added.
The results were recorded following each cation, noting the color, clarity and appearance (texture).
Next, for each solution in which a precipitate formed (Zn2+, Cu2+, Co2+) an additional 10 drops of 6M
NaOH were added to each centrifuge tube individually and the results recorded. The contents of the centrifuge tubes were then disposed of in
Chem 111 Sec 560
Introduction: The purpose of this lab was to study the specific characteristics of cations and anions, and ultimately to be able to identify an unknown substance based on our studies and tests using the logic trees developed through the experiment. A logic tree is a graphical display of the findings from this lab which, through a series of yes/no questions, elimination tests, will help us to identify and unknown sample. This lab will result in 2 logic trees, one for identifying cations and the other, anions.
The lab was broken into three parts: Part 1 dealt with identifying a cation, Part 2 an anion, and finally
Part 3 an unknown salt mixture of anions and cations was identified using the same tests in Part 1 and
2.
Materials and Methods: Part 1: Cation Analysis: The experiment was performed on 4 cations: K+,
Zn2+, Cu2+, and Co2. To begin the elimination and confirmation tests, 4 centrifuge tubes were prepared by adding 10 drops of each known cation in metal solution; the tubes were labeled accordingly. The first test performed was the Metal Hydroxide Test, wherein drops of 6 M NaOH were added dropwise to each tube until a precipitate was formed, or a total of 20 drops were administered. This process was repeated for each tube, with drops administered until a precipitate was visible. Drops were administered as follows:K+: 20 drops, Zn2+: 3 drops, Cu2+: 2 drops, Co2+: 2 drops 6 M NaOH added.
The results were recorded following each cation, noting the color, clarity and appearance (texture).
Next, for each solution in which a precipitate formed (Zn2+, Cu2+, Co2+) an additional 10 drops of 6M
NaOH were added to each centrifuge tube individually and the results recorded. The contents of the centrifuge tubes were then disposed of in